Endocrinology Exam Questions

Correct Answer: A

Rationale: Phaeochromocytoma is a rare neuroendocrine tumor that usually originates from the adrenal glands and produces excess catecholamines. The characteristic symptoms of phaeochromocytoma include paroxysmal (sudden and severe) hypertension, fear of impending death (angor animi), and episodic symptoms like palpitations, headache, and diaphoresis. However, weight gain is not a typical manifestation associated with phaeochromocytoma. In fact, patients with this condition may experience unintentional weight loss due to the effects of excess catecholamines on metabolism and appetite suppression. Therefore, weight gain is not a significant feature observed in individuals with phaeochromocytoma.

Correct Answer: A

Rationale: Centripetal obesity, acne, and hirsutism are classic features of Cushing's syndrome. Cushing's syndrome results from prolonged exposure to high levels of cortisol, which can be due to various causes such as adrenal tumors, pituitary adenomas, or exogenous glucocorticoid use. Centripetal obesity refers to the characteristic fat distribution pattern seen in Cushing's syndrome, where fat accumulates mainly in the face, neck, and trunk while sparing the limbs. Acne and hirsutism are also commonly seen in Cushing's syndrome due to the hormonal imbalances caused by excess cortisol. Testing for serum cortisol levels, dexamethasone suppression tests, and imaging studies can help confirm the diagnosis of Cushing's syndrome in a patient presenting with these symptoms.

Correct Answer: C

Rationale: The phrase "Cushing's disease" specifically refers to the cause of Cushing's syndrome that is due to an ACTH-secreting pituitary adenoma. In this specific case, the excess production of ACTH leads to bilateral adrenal hyperplasia and oversecretion of cortisol. It is important to differentiate between Cushing's syndrome caused by a pituitary adenoma (Cushing's disease) and other causes such as adrenal adenomas, ectopic ACTH production, or iatrogenic sources.

Correct Answer: D

Rationale: Addison's disease, also known as primary adrenal insufficiency, is mainly caused by the autoimmune destruction of the adrenal cortex. This results in the inadequate production of hormones such as cortisol and aldosterone by the adrenal glands. While other conditions such as Adrenoleukodystrophy, Pyelonephritis, and Tuberculosis can also affect the adrenal glands, they are not known to be direct causes of Addison's disease.

Correct Answer: A

Rationale: In the syndrome of inappropriate antidiuretic hormone (SIADH), there is excessive secretion of antidiuretic hormone (ADH) leading to increased water reabsorption in the kidney tubules. This results in dilutional hyponatremia because the amount of water reabsorbed is greater than the electrolytes, such as sodium, leading to a relative decrease in their concentration in the blood. As a result, hyponatremia occurs in SIADH, contributing to symptoms such as nausea, confusion, and seizures due to the imbalance in electrolytes.